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13 Articles in Volume 18, Issue #9
Children, Opioids, and Pain: The Stats & Clinical Guidelines
How to Fit into a New Practice
How to Talk to Your Chronic Pain Patients
How to Treat Opioid Use Disorder in Pregnant Women
Intranasal Ketamine for Acute Pain in Children
Medication Selection for Comorbid Pain Management (Part 3)
MR Neurography: Using Peripheral Nerve Imaging as a Pain Diagnostic
Naloxone in Schools; Buprenorphine Conversions; OUD Management
Opioid Conversion Calculations and Changes
Pes Anserine Tendino-Bursitis as Primary Cause of Knee Pain in Overweight Women
Self-Management of Chronic Pain in Primary Care
The Homebound Adolescent: Managing Chronic Pain Conditions in the Pediatric Population
The Opioid Band-Aid: The State of Pain Pills, Congressional Bills, and Healthcare in the US

Pes Anserine Tendino-Bursitis as Primary Cause of Knee Pain in Overweight Women

A retrospective study of pes anserine corticosteroid injections in treating chronic knee pain in women with and without osteoarthritis.
Pages 37-42 ; 50
Page 1 of 3

Obese individuals are at increased risk of developing knee osteoarthritis.1,2 A “vicious cycle” has been described in which joint pain leads to decreased physical activity; the subsequent weight gain produces increased joint surface forces, thus accelerating the development of osteoarthritis (OA) and disabling knee pain.3 Women, especially those of ethnic minority groups, have been found to be disproportionately affected by this pattern.3

Decreasing the knee pain to tolerable levels may allow an individual to live a more active life, and perhaps break the cycle. Whereas knee arthroscopy has been the mainstay of treatment for those with less advanced disease, multiple studies have shown that partial meniscectomy is generally ineffective in patients with degenerative knees,4-6 especially in overweight individuals.7 Obese individuals are also prone to develop comorbidities, such as diabetes and heart disease, and thus present an increased risk with invasive procedures such as total knee replacement.8 Because the problem of knee pain in overweight women with OA has proven difficult to treat, perhaps understanding the possible pathogenesis of knee pain in this patient population would be clinically beneficial.

In 1937, Eli Moshkowitz, MD, described a painful knee condition in overweight women who were tender in the pes anserine region and not on the joint line.9 The pes anserinus (“goose foot”) consists of the tendinous attachments of the semitendinosus, gracilis, and sartorius muscles. A bursa exists underneath these tendons, and its location has been well-described in an anatomical study.10 The term “pes anserine tendino-bursitis,” or PATB, is now used to describe this condition. A few studies have shown that PATB may contribute to knee pain in patients with OA.11,12 Injection of the pes bursa with corticosteroid has shown to be an effective treatment, including in patients with OA.13,14

A retrospective study of pes anserine corticosteroid injections in treating chronic knee pain in women with and without osteoarthritis. (Source: 123RF)

There have been few studies, however, that have looked at the prevalence of PATB. One investigation using MRI identified pes bursitis in 2.5% of patients with knee pain.15 Two studies in which ultrasound was utilized on patients with painful knee OA found an incidence of pes anserine bursitis in 8 and 20%, respectively.16,17 There are no published reports on the prevalence of PATB specifically in overweight women. An association between obesity and PATB has not been proven, and one study even showed that obesity was actually not a risk factor.12

The goals of this case study are to identify the frequency of PATB in overweight mature women who present with severe knee pain, and to determine the effectiveness of treatment with a steroid injection into the pes anserine region. If reducing the pain in the pes anserinus significantly decreases the patient’s symptoms, even in the presence of osteoarthritis, this result would suggest that PATB is a significant contributor, if not the main source, of their pain.

Methods & Patient Base

The Clinica de Salud del Valle de Salinas Institutional Review Board, in Salinas, California, made a determination of “EXEMPT” with respect to Human Subject Research requirements. This paper therefore offers a retrospective review of medical records of overweight women with knee pain treated between January 1, 2015 and January 1, 2017 in an outpatient clinic setting using a treatment approach based solely on history and physical examination, specifically focusing on the area of maximum tenderness.

During this time period, 196 consecutive overweight (BMI 25 or over) women age 40 and older, involving 260 knees, presented with a chief complaint of knee pain lasting at least two months and not associated with significant recent trauma (eg, fracture or cruciate ligament tear). All patients had a pain assessment using a Visual Analog Pain Score (VAS) and were given a pain score ranging from 0 to 10.

Patients included in the study (115 patients/148 knees) had “severe knee pain” (6 or higher VAS), and had received some form of conservative management (eg, NSAIDS or other pain medication, physical therapy, and/or exercises) with at least four weeks follow-up. Patients included in the review had a functional range of motion (5 to 90 degrees at minimum).

Six patients with far advanced OA with limited knee range of motion and/or severe deformity (ie, greater than five degrees varus and 15 degrees of clinical valgus) were excluded. Also excluded were 51 patients with mild/moderate pain who improved with conservative treatment and 27 patients for whom there was no follow-up after the first visit (six in this group had received an injection.)

Assessment & Treatment

In addition to a history and pain assessment, a complete knee examination was performed in the supine position. In addition, leg strength was assessed by ability to perform straight leg raises against resistance.

For the study examination, the patients were placed in a sitting position with the knee flexed over the edge of the table to 90 degrees. Palpation was performed, which included the femoral condyles, joint lines, patella area, and patellar tendon (labeled #1-6 in Figure 1a). To help find the location of maximum tenderness in the pes region, a horizontal line was drawn in the proximal medial tibia between the tibial tubercle anteriorly and the apex of the knee flexion crease posteriorly (see Figure 1a).

For each patient, the location of maximum tenderness was identified and recorded. The area of maximal tenderness in the pes anserine area was consistently found approximately one centimeter posterior to the center of this line (see “X” #7 in Figure 1a). If the maximum tenderness was identified in the pes area (“#7”), the patient was diagnosed with pes anserine tendino-bursitis, and offered an injection into that specific location. Those with tenderness elsewhere were treated according to the diagnosis.

Patients opting for the injection signed the consent for the procedure explaining the risks and benefits. After sterile preparation, the injection was done using a one-and-a-half-inch long 22-gauge needle with an entry angle of approximately 45 degrees to the coronal plane of the tibia angling from anteromedial to posterolateral. A longer needle is not used to avoid any possibility of trauma to the neurovascular structures posteriorly (see Figure 1b). Lidocaine (5 cc of 1%) in one syringe is injected into the subcutaneous and deeper layers all the way to bone, and then, without removing the needle, steroid (80 milligrams of kenalog) from a second syringe is injected around the bone (see Figure 1c). It should be noted that in all cases the one and a half inch long needle was sufficient to reach the bone, and occasionally required “puckering” of the tissues (see Figure 1c).

Figure 1, left to right: a) Locating maximum tenderness in the pes region; b) use of a one-and-a-half-inch 22-guage needle with an entry angle of approximately 45 degrees to the coronal plane of the tibia; and c) injection of steroid by second syringe around the bone. (Images courtesy of the author.)

Last updated on: December 5, 2018
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Successful Nonoperative Treatment of Persistently Painful Knees Following Total Knee Arthroplasty—A Case Series